The first six victims died in July 1977, when Ferguson entered a home in Carol City by posing as Florida Power & Light employee. After searching a few rooms, he pulled a gun and tied up a woman inside. He then let in two accomplices, Marvin Francis and Beauford White.

The three were looking for money and drugs when the home's owner, Stocker, and six friends arrived. The robbers tied the men up and then later shot them all, execution-style. The woman and one of the men survived despite a shotgun blast to the head, but Stocker and five others died.

Ferguson also later confessed to another horrific crime. In January 1978, he raped and murdered Worley and killed her boyfriend, Glenfeldt; they were both 17 years old.

The two accomplices in the home invasion, Francis and White, were executed in the late '80s.

Ferguson had stalled his own execution for decades by pleading mental illness and claiming to be incompetent to aid his defense attorneys.

Here's the full death warrant, which calls for Ferguson's execution to be carried out October 16 at 6 p.m.: